[src/trunk]: src/sys No need to cache anonymous device vnodes, they will neve...

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3687fe4ce6a6
branches:  trunk
changeset: 355905:3687fe4ce6a6
user:      hannken <hannken%NetBSD.org@localhost>
date:      Mon Aug 21 08:56:45 2017 +0000

description:
No need to cache anonymous device vnodes, they will never be looked up.

Set key to (dead_rootmount, 0, NULL) and add assertions.

diffstat:

 sys/kern/vfs_vnode.c            |  62 ++++++++++++++++++++++++----------------
 sys/miscfs/deadfs/dead_vfsops.c |   8 ++--
 2 files changed, 41 insertions(+), 29 deletions(-)

diffs (138 lines):

diff -r f4117f2fb3c0 -r 3687fe4ce6a6 sys/kern/vfs_vnode.c
--- a/sys/kern/vfs_vnode.c      Mon Aug 21 07:38:42 2017 +0000
+++ b/sys/kern/vfs_vnode.c      Mon Aug 21 08:56:45 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_vnode.c,v 1.96 2017/06/04 08:05:42 hannken Exp $   */
+/*     $NetBSD: vfs_vnode.c,v 1.97 2017/08/21 08:56:45 hannken Exp $   */
 
 /*-
  * Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -156,7 +156,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.96 2017/06/04 08:05:42 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.97 2017/08/21 08:56:45 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -1028,6 +1028,8 @@
 {
        uint32_t hash = HASH32_BUF_INIT;
 
+       KASSERT(key->vk_key_len > 0);
+
        hash = hash32_buf(&key->vk_mount, sizeof(struct mount *), hash);
        hash = hash32_buf(key->vk_key, key->vk_key_len, hash);
        return hash;
@@ -1381,23 +1383,29 @@
                KASSERT(*vpp == NULL);
                return error;
        }
-       KASSERT(vip->vi_key.vk_key != NULL);
        KASSERT(vp->v_op != NULL);
-       hash = vcache_hash(&vip->vi_key);
+       KASSERT((vip->vi_key.vk_key_len == 0) == (mp == dead_rootmount));
+       if (vip->vi_key.vk_key_len > 0) {
+               KASSERT(vip->vi_key.vk_key != NULL);
+               hash = vcache_hash(&vip->vi_key);
 
-       /* Wait for previous instance to be reclaimed, then insert new node. */
-       mutex_enter(&vcache_lock);
-       while ((ovip = vcache_hash_lookup(&vip->vi_key, hash))) {
-               ovp = VIMPL_TO_VNODE(ovip);
-               mutex_enter(ovp->v_interlock);
+               /*
+                * Wait for previous instance to be reclaimed,
+                * then insert new node.
+                */
+               mutex_enter(&vcache_lock);
+               while ((ovip = vcache_hash_lookup(&vip->vi_key, hash))) {
+                       ovp = VIMPL_TO_VNODE(ovip);
+                       mutex_enter(ovp->v_interlock);
+                       mutex_exit(&vcache_lock);
+                       error = vcache_vget(ovp);
+                       KASSERT(error == ENOENT);
+                       mutex_enter(&vcache_lock);
+               }
+               SLIST_INSERT_HEAD(&vcache_hashtab[hash & vcache_hashmask],
+                   vip, vi_hash);
                mutex_exit(&vcache_lock);
-               error = vcache_vget(ovp);
-               KASSERT(error == ENOENT);
-               mutex_enter(&vcache_lock);
        }
-       SLIST_INSERT_HEAD(&vcache_hashtab[hash & vcache_hashmask],
-           vip, vi_hash);
-       mutex_exit(&vcache_lock);
        vfs_insmntque(vp, mp);
        if ((mp->mnt_iflag & IMNT_MPSAFE) != 0)
                vp->v_vflag |= VV_MPSAFE;
@@ -1556,10 +1564,12 @@
        } else {
                temp_key = temp_buf;
        }
-       mutex_enter(&vcache_lock);
-       memcpy(temp_key, vip->vi_key.vk_key, temp_key_len);
-       vip->vi_key.vk_key = temp_key;
-       mutex_exit(&vcache_lock);
+       if (vip->vi_key.vk_key_len > 0) {
+               mutex_enter(&vcache_lock);
+               memcpy(temp_key, vip->vi_key.vk_key, temp_key_len);
+               vip->vi_key.vk_key = temp_key;
+               mutex_exit(&vcache_lock);
+       }
 
        fstrans_start(mp);
 
@@ -1604,13 +1614,15 @@
        /* Purge name cache. */
        cache_purge(vp);
 
+       if (vip->vi_key.vk_key_len > 0) {
        /* Remove from vnode cache. */
-       hash = vcache_hash(&vip->vi_key);
-       mutex_enter(&vcache_lock);
-       KASSERT(vip == vcache_hash_lookup(&vip->vi_key, hash));
-       SLIST_REMOVE(&vcache_hashtab[hash & vcache_hashmask],
-           vip, vnode_impl, vi_hash);
-       mutex_exit(&vcache_lock);
+               hash = vcache_hash(&vip->vi_key);
+               mutex_enter(&vcache_lock);
+               KASSERT(vip == vcache_hash_lookup(&vip->vi_key, hash));
+               SLIST_REMOVE(&vcache_hashtab[hash & vcache_hashmask],
+                   vip, vnode_impl, vi_hash);
+               mutex_exit(&vcache_lock);
+       }
        if (temp_key != temp_buf)
                kmem_free(temp_key, temp_key_len);
 
diff -r f4117f2fb3c0 -r 3687fe4ce6a6 sys/miscfs/deadfs/dead_vfsops.c
--- a/sys/miscfs/deadfs/dead_vfsops.c   Mon Aug 21 07:38:42 2017 +0000
+++ b/sys/miscfs/deadfs/dead_vfsops.c   Mon Aug 21 08:56:45 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dead_vfsops.c,v 1.7 2015/07/01 08:13:53 hannken Exp $  */
+/*     $NetBSD: dead_vfsops.c,v 1.8 2017/08/21 08:56:45 hannken Exp $  */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dead_vfsops.c,v 1.7 2015/07/01 08:13:53 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dead_vfsops.c,v 1.8 2017/08/21 08:56:45 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -108,8 +108,8 @@
        uvm_vnp_setsize(vp, 0);
        spec_node_init(vp, vap->va_rdev);
 
-       *key_len = sizeof(vp->v_interlock);
-       *new_key = &vp->v_interlock;
+       *key_len = 0;
+       *new_key = NULL;
 
        return 0;
 }